Broaching Risk in Following Seas
Broaching-to risk rises when wave celerity c exceeds 1.8·V_ship AND wave length is 1–3 × LBP.
Wave celerity
16.76m/s
c / V_ship
2.72 -
λ / L
1.20 -
Broaching risk
Moderate or low risk
Formula, assumptions, and limits
Deep-water wave celerity. Broaching (sudden yaw forced by passing following wave) is most dangerous for fast ships in astern seas with λ > L. Rule of thumb: reduce speed and quarter the seas (45° off stern) when c/V < 1.8.
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| Deep-water wave celerity | m/s | derived | |
| Wave length | m | input | |
| Ship speed | m/s | derived |